This invention is directed to power driven rotary data storage and retrieval files of the large type used for carrying heavy articles, such as a large number of telephone directories, or the like; and it is directed to providing improvements in such structures.
Files of this general nature include a supporting post upon which a frame carrying a circular container or pan is mounted for relative rotation by means of a motorized drive acting through a friction slip-clutch connection with the frame. In using the apparatus, the operator energizes the motor causing the frame to rotate at a slow speed. As a desired particular section of the pan on the frame approaches the operator, he shuts off the power causing the frame to coast gradually to a stop, bringing the selected section before him.
The friction-slip clutch is necessitated by the momentum generated by the heavy load on the frame which continues the rotation of the frame briefly after the power has been cut off. However, a fault of the conventional friction clutch used in these structures lies in its structure whereby the load of the frame and its contents is borne by the clutch. This creates problems in start up, problems in wear of the clutch mechanism, and problems in obtaining a desirable slow coasting of the apparatus to a stop following power shut-off.
Another fault of known files lies in the structure of the container or pan. This has been found to be an integral circular unit which, because of its considerable weight and large size, approximately 8 to 10 feet in diameter, creates problems in transportation, in porting the unit through doorways, and in assembling it upon the frame.
The general objective of the present invention is to provide an improved rotary data storage and retrieval file of the large type which avoids the faults mentioned.
A feature of the invention lies in the nature of the friction-slip clutch which transmits the power drive to the frame. It is structured so that the load of the rotary wheel frame is borne by the supporting post and not by the clutch. An advantageous characteristic of the clutch lies in simple means for adjusting the pressure load for determining the friction engagement and slipping point of the clutch.
Some of the advantages derived from the improved clutch are reduced wear of its components; improved start-up, and desirable coasting and stopping after power shut-off.
Another feature lies in the structure of the data container or pan unit and in the associated wheel frame. The annular pan unit is not a single unit; but comprises a group, or plurality of separable segments or sections which, when assembled upon the frame, make up a full annular unit. Also, the frame is provided with spokes to support the several sections and to allow easy and quick assembly thereon. In the illustrated embodiment herein the pan unit is shown as comprising four separable segments of 90.degree. each.
As is evident, a particular advantage of making the pan unit in sections is the ease of transportation, and assembly that results from such an arrangement.